1. Field of the Invention
The present invention relates to a portable electronic device and a control method for controlling the portable electronic device and, more particularly, to a technique for reducing the power consumption of an electronically controlled timepiece having an analog hand.
2. Description of the Related Art
Small wristwatch-type electronic watches, equipped with a generator such as a solar cell and operable without the need for any battery replacement, have been developed. These electronic timepieces function by initially charging a high-capacitance capacitor with power generated by a generator, and then providing a time display operated from power discharged by the capacitor when no primary power is being generated. For this reason, reliable operation over long periods of time is possible without batteries. Considering the time required to replace a battery and the problem associated with the disposal of a battery, more and more electronic timepieces are expected to be equipped with a generator.
The generator built in the wristwatch may be a solar cell that converts incident light into electrical energy, or a power generating system that converts kinetic energy into electrical energy taking advantage of the motion of a user""s arm. These generators are very advantageous in that energy surrounding the user is converted into electrical energy, but the density of usable energy is low, and the availability of energy is not continuous.
The generator cannot continuously generate power, and when no power is generated, the electronic timepiece is operated from power stored in a high-capacitance capacitor. For this reason, the high-capacitance capacitor preferably has a capacitance as large as possible, but the electronic wristwatch cannot house the capacitor if its size is too large. Since it takes time to charge the capacitor, a voltage having an appropriate level is difficult to obtain. On the other hand, with a low-capacitance capacitor, the electronic watch will stop if the duration of non-power generation is lengthened, and even if the electronic watch starts its operation with light coming back on again, the time display suffers from an error with inaccurate current time presented. As a result, the electronic timepiece fails to perform its function as a watch.
Since a wristwatch device employing a solar cell can detect ambient illuminance using a solar cell, the following system has been proposed: when illuminance drops below a set value, for example, during nighttime, the system measures, with its internal counter, the time during which a time displaying stops (in a power save mode), and when luminance gets stronger in the morning, the time displaying is resumed, and the system reverts back to its current time (in a normal operation mode).
However, users often want to check time during nighttime, and the inability to make instant access to the current time inconveniences the users. Occasionally, the wristwatch is not well exposed to light in winter, because people put on overcoats, and the wristwatch stops, failing to perform its expected function. When the wristwatch is not worn and is left in a room, weak light may be incident on the wristwatch, causing it to operate and thereby consuming electric power in vain.
Since when to shift from the normal operation mode to the power save mode is determined by a control unit in the wristwatch rather than at the user""s own discretion, the optimum power saving performance matching the usage of the wristwatch by the user is not fully promoted. The shifting into the power save mode is not freely commanded at each of the stages of assembly, inspection and packing in a plant, during the transportation from the plant to retailers, and at a storage stage, and power consumption is not reduced.
Therefore, it is an object of the present invention to overcome the aforementioned problems.
It is another object of the present invention to provide a portable electronic device and a control method for controlling the portable electronic device, which is easily shifted into the power save mode at the discretion of a particular individual for example, users, manufacturers, retailers, or other people, thereby reducing power consumption to an optimum level in accordance with each individuals use.
The following summarizes the various embodiments of the present invention. Not all features summarized here are required to achieve all objects of the invention. The present invention includes power generating means or power generator which performs power generation by converting first energy into second energy that is electrical energy, a power source for storing electrical energy resulting from the power generation, driven means or unit driven by the electrical energy supplied by the power source, operation means or unit on which a user performs a variety of operations, operational state determining means or unit for determining whether an operational state of the operation unit is a predetermined operational command state to shift into a power save mode for reducing a power consumption of the driven unit, and operation mode control means or controller for shifting an operation mode into the power save mode in accordance with the determination result provided by the operational state determining unit.
The operation means or unit includes an operation control which the operator operates, and a position detector for detecting a position of the operation control.
The operational state determining unit determines that the operation unit is in an operational command state to shift into the power save mode if the operation control is moved from a first position to a second position and is then moved back to the first position from the second position within a predetermined duration of time.
A carried state detector detects whether the portable electronic device is in a carried state in which an operator is carrying the portable electronic device, wherein, in accordance with the detection result provided by the carried state detector, the operation mode controller shifts the operation mode of the driven unit from a normal operation mode to the power save mode to reduce the power consumption of the driven unit when the electronic device is in a non-carried state.
The carried state detector detects, based on a generation state of the power generator, whether the portable electronic device is in a carried state in which an operator is carrying the portable electronic device.
The first energy is one of kinetic energy, pressure energy and thermal energy.
When the first energy is one of optical energy and electromagnetic energy, and the operation mode controller shifts the operation mode of the driven unit to the power save mode when the portable electronic device is in a non-carried state and when the power generator is in a predetermined generation state corresponding to the power save mode.
The driven unit may be a time display means for presenting a time display.
The operation unit may include a crown which the operator operates, and the position detector detects the position of the crown.
The operational state determining unit determines that the operation unit is in an operational command state to shift into the power save mode if the crown is moved from a first position to a second position and is then moved back to the first position from the second position within a predetermined duration of time.
The time display may include an analog hand for presenting an analog time display, and hand drive unit drives the analog hand, wherein the operation mode controller includes an operation stopper for stopping the operation of the hand drive unit throughout the power save mode.
An elapsed time counter counts elapsed time from the start of the power save mode, when the operational state of the operation unit is changed to an operational command state to shift into the power save mode, and a return to current time display unit returns the display on the time display to the current time, and accounts for the elapsed time in accordance with the count provided by the elapsed time counter, when the power save mode is shifted to the normal operation mode.
A control method of the present invention for controlling a portable electronic device including an operation control on which an operator, such as a user, performs a variety of operations, a power source stores electrical energy, and a driven unit is driven by the electrical energy, includes a power generating step for generating power by converting first energy into second energy that is electrical energy, an operational state determining step for determining whether an operational state of the operation control is a predetermined operational command state to shift into a power save mode for reducing a power consumption of the driven unit, and an operation mode control step for shifting an operation mode into the power save mode in accordance with the determination result provided in the operational state determining step.
The operational state determining step may include a position detecting step for detecting a position of the operation control.
The operational state determining step determines that the operation control is in an operational command state to shift into the power save mode if the operation control is moved from a first position to a second position and is then moved back to the first position from the second position within a predetermined duration of time.
A carried state detecting step detects whether the portable electronic device is in a carried state in which an operator is carrying the portable electronic device, wherein, in accordance with the detection result provided in the carried state detecting step, the operation mode control step shifts the operation mode of the driven means from a normal operation mode to the power save mode to reduce the power consumption of the driven unit when the portable electronic device is in a non-carried state.
A generation state in the power generating step is considered when the carried state detecting step detects whether the portable electronic device is in a carried state in which the operator is carrying the portable electronic device.
The driven unity may be a time display and the operation control may be a crown that the operator operates, and the operation mode determining step may include the position detecting step for detecting a position of the crown.
The operational state determining step determines that the crown is in an operational command state to shift into the power save mode if the crown is moved from a first position to a second position and is then moved back to the first position from the second position within a predetermined duration of time.
The time display may include an analog hand for presenting an analog time display, and a hand driver for driving the analog hand, and the operation mode control step includes an operation stop step for stopping the operation of the hand driver during the power save mode.
An elapsed time counting step counts elapsed time from the start of the power save mode, and when the operational state of the operation unit is changed to an operational command state to shift into the power save mode, the return to current time display step for returning the display on the time display to the current time, accounts for the elapsed time in accordance with the count provided in the elapsed time counting step, when the power save mode is shifted to the normal operation mode.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.